Car Not Starting

I am haveing troble fixing my car. It is a 93' Civic SI with a stock d16z6 with nothing done. It will not start with the key(i have to push start it). The has been happening for about a month or so. So far i have replace the starter, spark plugs, spark plug wires, cap and rotor botton, ground and power cable on the battery, the battery, the fuel Filter, and air filter(all of the parts are brand new OEM honda parts). I was hopeing someone might be able to point me in the right direction to get this fixed.

I would test your ignition switch, what does it do when you turn the key? Your main relay mabey... but you said you can start the car with push starting it, which means its getting fuel. So by the sounds of it, the relay is ok. If it doesnt even crank the motor when you turn the key then more then likey its that switch.